酸催化蒸汽爆破预处理提高蔗渣酶解性能研究

Studyof Acid-cata lyzes Steam Explosion Pretreatm ent to Enhance the Enzym atic D igestib ilityof Sugar Cane Bagasse

采用常规蒸汽爆破以及酸催化蒸汽爆破对甘蔗渣进行预处理,利用扫描电镜(SEM)对比观察这两种汽爆方法对残渣表面结构形态的影响,对比分析汽爆液的糖类、汽爆残渣组分,最后通过纤维素酶解试验评价汽爆残渣的酶解性能。结果表明,常规蒸汽爆破和酸催化蒸汽爆破均能提高蔗渣原料的酶解性能,但是常规蒸汽爆破需要在较高的处理压力(>2.0MPa)下才能明显水解半纤维素,破坏纤维素的天然结晶结构,显著提高蔗渣的酶解性能。酸催化蒸汽爆破只需很低的汽爆压力(0.7MPa)就能充分水解蔗渣半纤维素,而且对蔗渣纤维天然结构的破坏程度也要大得多,残渣的酶解率达到49.1%,比常规同一蒸汽爆破压力条件下的酶解率(25.1%)几乎高出一倍。酸催化汽爆残渣的酶解性能随汽爆压力的提高而改善,从半纤维素到木糖的收率则随压力的升高而降低,采取两步蒸汽爆破法,将可以同时获得高的木糖收率和高的纤维素酶解效率。

Conventional steam explosion and acid-catalyzes steam explosion were performed to the pretreatment of sugar cane bagasse.SEM were applied to observe the differences of appearance and structure between the residual solids through these two ways.The kinds of sugar in liquid phaseand the components of residual solid were analyzed comparably,cellulase hydrolyzation was performed to evaluate the enzymatic cellulose digestibility of residual solid.The results showed that both of the two ways could enhance the enzymatic cellulose digestibility of the bagasse,but high presses（〉2.0MPa） in conventional steam explosion preatreament were necessary to cause the hydrolyzation of hemicellulose and the breakage of crude crystal structure of cellulose,and to enhance the enzymatic cellulose digestibility of sugar bagasse evidently.However,a lower steam pressure（0.7MPa） in acid-catalyzes steam explosion pretreatment could cause the hydrolyzation of hemicellulose adequately and more breakage of crude crystal structure of cellulose,the enzymatic cellulose digestibility of the residue were up to 49.1%,which was near one time as much as 25.1% of conventional steam explosion in the same pressure.The enzymatic digestibility of residue pretreated by acid-catalyzes steam explosion was improved as the steam pressure increased,but xylose yield from hemicellulose was reduced as the presses increased.The two-steps acid catalyzes steam explosion pretreatment,could obtain high xylose conversion levels from hemicellulose and high enzymatic cellulose digestibility of sugar cane bagasse synchronously.